The science of protecting avulsed teeth has progressed little in the past 10 years. While commercial solutions are available, most simply consist of a pH balanced salt solution. Several peer-reviewed citations in the last two years have compared the efficacy of Save-A-Tooth, other salt formulations, coconut water and milk as candidates for maintaining avulsed teeth until such time that they can be implanted. In some of these cases skim milk and Hank's Balanced Salt Solution (HBSS) have the greatest capacity to maintain the viability of the critical periodontal ligament fibroblasts (PDLF). In response to the lack of a scientifically sound, tooth-specific, holding medium this project proposes to develop ToothGuardTM - a new normothermic (20 to 37oC) medium designed to maintain the PDLF during the ex vivo holding interval based on the control of cell specific stress pathways activated by PDLF when they are removed from their native craniofacial environment. ToothGuard will be the first holding reagent designed both in a fully dehydrated (powder) and liquid format. The reagent will be formulated to protect PDLF during ex vivo holding at normothermic temperatures (room temperature) through the control of the cellular and molecular cell stress pathways activated in response to the stresses associated with tooth avulsion. The Specific Aims are as follows: (1) Identify the cell stress pathways activated in PDLF under conditions that they would experience in situ when present in an avulsed tooth; (2) Identify inhibitors that will maintain PDLF by ameliorating the stress pathway response and test these agents individually on PDLF when they are subjected to avulsion-like stress regimes; and (3) Formulate two ToothGuard prototypes and compare them for their respective effectiveness against Save-A-Tooth, HBSS and MEM. Phase 2 will be dedicated to optimizing ToothGuard, developing TGpak for treating inflammatory/non-inflammatory root replacement resorption, developing a unique transport device for the avulsed tooth and teaming with a pharmaceutical/dental supply company as well as a Boston area academic institution to test ToothGuard and TGpak in vivo. The sum consequence of this Phase 1 project will be the first thermally insensitive, room temperature, reagent developed to maintain avulsed teeth ex vivo based on the unique, cell stress pathways activated in PDLF when they are subjected to conditions experienced in an avulsed tooth. PUBLIC HEALTH RELEVANCE: CPSI Biotech intends to develop a unique solution designed to protect avulsed (knocked out) teeth prior to implantation. The innovation of this project is tha this product (ToothGuard) will be the first ever designed based on the individual stress pathways that are activated by the key cells (periodontal ligament fibroblasts) when they are removed from their native craniofacial environment. Teeth stored in ToothGuard will have a higher chance of successful re-implantation compared to teeth stored in alternative solutions such as Save-A-Tooth and milk.